Brief description
Seismic reflection traverses were surveyed across the Perth Basin at Cookernup, W.A. These traverses were planned to find the thickness and dip of the Basin sediments adjacent to the Darling Scarp and to discover any faulting or folding within them; also to determine the applicability of the seismic method as a tool for both regional and detailed investigation in this area. Seismic refraction traverses were surveyed to help in the solution of problems encountered in the interpretation of the reflection cross-sections. The survey indicated a considerable thickness of sediments about 20,000 ft, at the eastern margin of the Basin near the Darling Scarp, and suggested tectonic structure that is not indicated in surface geology, The reflection traverses indicated that sediments (presumably Lower Palaeozoic or Precambrian) lying deep in the Perth Basin may continue underneath the Darling Scarp and abut the granitic gneisses etc. of the Western Australian Shield on an overthrust fault plane. The overthrust fault, if it exists, does not reach the surface, but is covered to a depth of possibly some few hundred feet by younger sediments and also by alluvium eroded from the Darling Scarp. Some reflection and refraction shooting was done in an attempt to test this and other hypotheses, but the results crc inconclusive. Gravity results strongly suggest a normal fault, and if normal faulting is the case, the reflections from beneath the outcropping basement are possibly derived from shear zones, Some probable 'reflected refractions' were also observed. There is scope for further seismic testing but it is considered that conclusive evidence could only be provided by drilling.Lineage
Maintenance and Update Frequency: asNeededIssued: 1962
Data time period: 1956-01-01 to 1956-01-01
text: westlimit=115.5; southlimit=-33.25; eastlimit=116.0; northlimit=-32.75
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https://d28rz98at9flks.cloudfront.net/76386/L027_Cookernup_1956_GeoCat_76386.zip
- URI : pid.geoscience.gov.au/dataset/ga/76386
- global : de71c515-71f1-04f0-e044-00144fdd4fa6